docs: def register_as_default(language: Language):
      """
      Registers a coverage extractor class as the default coverage extractor
      for a given language. Requires that the coverage extractor class has
      already been registered with a given name.
  
      .. code: python
  
          from bugzoo.core import Language
          from bugzoo.mgr.coverage import CoverageExtractor, register, \
              register_as_default
  
          @register_as_default(Language.CPP)
          @register('mycov')
          class MyCoverageExtractor(CoverageExtractor):
              ...
      """
      def decorator(cls: Type['CoverageExtractor']):
          cls.register_as_default(language)
          return cls
      return decorator